Zefram, Ah yes, I'd forgotten about the 'version' file; definitely the way to check for updates. Thanks for the clarification about the zone1970.tab contents. So maybe I can program the clock to make a once-only access to a TZdb mirror for that file, at first start-up, to fetch the region/cities list for the owner to choose from. If something ever changed to make that choice invalid, there could be a service routine in the firmware that allowed the user to re-do this once-only download for a new region/city selection. (Whew, things are getting complicated! :-) But the most exciting part of your e-mail was the mention of the IETF working group! I went there and found that they had concluded their work and issued RFC7808. I downloaded that and read it, and think that the "expand" Action is just what I'm looking for! So all I need to do is find one or more TZDIST servers that look like they should be around for the long-term. To my (simple) way of thinking, it would make sense if (some) NTP servers added this TZDIST functionality, so they became a 'one-stop-shop' for current time information, but whether they have/will is another matter. I'll start looking. Thanks again for the tip-off. Regards, Daniel